If booting from CD/DVD then the parameters are set at the prompt shown before Puppy boots. Usually, if no key is pressed after 5 seconds then Puppy will load with default settings. Example: puppy pkeys=us

With frugal installation the parameters are set by one of the Boot Loader's files. GRUBand GRUBforDOS use the 'menu.1st' file.
title Puppy Linux 525
rootnotify (hd0,0)
kernel (hd0,0)/vmlinuz pmedia=atahd psubdir=puppy525
initrd (hd0,0)/initrd.gz

"...Pfix=nox doesn't work in full install because the code that interprets this only exists in initrd.gz, and full-install doesn't use initrd.gz. (In fact, all other puppy boot parameters will not work in full install)"see forum

Read the documentation included with other boot loaders for where to include these parameters. The parameters are case-sensitive, so ensure it's exactly as shown. Additionally, vmlinuz is the filename of the kernel image that one would need to specify when using a boot loader. See the isolinux.cfg & boot.msg files in the CD image (.ISO) or on the CD/DVD for a little more on each version's normal boot options.